firmware: make emmc_pll_core enabled by default and handle turbo mode
See: https://github.com/raspberrypi/linux/issues/415#issuecomment-27763584

kernel: enable MROUTE options and CONFIG_CRYPTO_AES_ARM
See: https://github.com/raspberrypi/linux/issues/430
See: https://github.com/raspberrypi/linux/issues/358

firmware: audio_render: check for output space more frequently to avoid underrun
See: http://forum.stmlabs.com/showthread.php?tid=10118